As shown earlier, a more direct test of the specific training hypothesis can be obtained if tn, the total duration of the current Job, Is observed.
The results using equation (11) are shown in Table 6, using a small sample of individuals who left the Job they held in 1966 before 1969. The coefficient of the Interaction term (REM x CURRENT) is positive and significant as expected, thus rn pn « .0087. The coefficient of time remaining (REM) is negative and approaching statistical significance, thus pn – .0620. The implied estimate of rn about 14 percent. The results unambiguously suggest that the correlation between Job duration and Investment is a significant determinant of the distribution of earnings. The addition of these two variables Increases the explanatory power of the equation (the F statistic is 2.55, significant at the 10 percent level).